Accuracy of acetabular cup placement during anterolateral supine total hip arthroplasty using intraoperative fluoroscopy: a retrospective study.

BACKGROUND: In our institution, total hip arthroplasty (THA) is performed using the anterolateral supine (ALS) approach with intraoperative fluoroscopy. This study aimed to investigate and review the accuracy of acetabular cup placement in ALS-THA using intraoperative fluoroscopy. METHODS: A total of 142 patients with 154 joints (mean age 64.3 years, 30 males and 112 females) underwent ALS-THA with intraoperative fluoroscopy at the same institution. The target angle of the cup position was set at 40° for radiographic inclination (RI) and 5°-25° for radiographic anteversion (RA) based on the functional pelvic plane according to the pelvic motion during individual postural changes. The cup position angle was measured using postoperative computed tomography, and the error in the target angle was investigated. RESULTS: The target angle of RI was 40°, and the postoperative RI was 39.3° ± 4.3°. The target angle of the RA was 17° ± 2.6°, and the postoperative RA was 20.6° ± 3.7°. The absolute values of the error from the target angle were 3.6° ± 2.5° for RI and 4.2° ± 3.3° for RA. For RI and RA, 67.5% (104/154 joints) were within ± 5° of the target and 96.1% (148/154 joints) were within ± 10°. CONCLUSIONS: The accuracy of cup positioning in ALS-THA using intraoperative fluoroscopy was good and appeared comparable to that of various navigation systems.

MRI Findings of Muscle Damage after Total Hip Arthroplasty Using the Complete Muscle Preserving Anterolateral Supine Approach.

Background and Objectives: We performed anterolateral total hip arthroplasty (ALS THA) with the purpose of complete muscle-tendon preservation without muscle-tendon dissection. This study aimed to evaluate muscle damage in the periprosthetic hip joint muscles of patients undergoing ALS THA at 1-year post-operative hip magnetic resonance imaging (MRI). Materials and Methods: We evaluated changes in the muscle cross-sectional area (M-CSA) and fatty atrophy of the periprosthetic muscles. We also assessed the Harris hip score on pre-operative and 12-month post-operative MRI in 66 patients who underwent ALS THA. The grade of M-CSA atrophy was classified into no atrophy, slight atrophy, moderate atrophy, and severe atrophy. Fatty atrophy was classified as improved, no change, and worsened using the Goutallier classification. Results: More than 90% of patients' M-CSA had no atrophy in the obturator internus (Oi), obturator externus (Oe), gluteus medius (Gmed), and gluteus minimus (Gmin), and some improvement was observed in terms of fatty atrophy. In contrast, M-CSA of the tensor fascia latae (TFL) muscle was clearly decreased, and there was no improvement in the TFL fatty atrophy. However, the presence or absence of TFL atrophy did not affect clinical outcome. Conclusions: We performed the complete muscle preserving procedure, ALS THA, with attention to preserving the Oi and Oe by direct visual confirmation and gentle treatment of the Gmed and Gmin with effective retraction. Post-operative M-CSA atrophy evaluation on MRI showed that the Oi, Oe, Gmed, and Gmin were satisfactorily preserved; however, the TFL was clearly atrophic. In the ALS approach, where entry is made between Gmed and TFL, atrophy of the TFL due to superior gluteal nerve injury must be tolerated to some extent.

Significant effect of the posterior tibial slope on the weight-bearing, midflexion in vivo kinematics after cruciate-retaining total knee arthroplasty.

The purpose of the present study was to compare weight bearing (WB) and non-WB conditions, and to evaluate the effect of the posterior tibial slope (PTS) on the in vivo kinematics of 21 knees after posterior cruciate ligament-retaining total knee arthroplasty during midflexion using 2-dimensional/3-dimensional registration. During WB, medial pivot and bicondylar rollback were observed. During non-WB, both the medial and lateral condyles moved significantly more anteriorly as compared to the WB state. These patients were divided into 2 groups according to their PTS. The large PTS group showed a significant posterior displacement of the medial femoral condyle as compared with the small PTS group, but no significant difference was observed at the lateral femoral condyle during both WB and non-WB. The PTS influenced knee kinematics through gravity (124/125).

Significant effect of the posterior tibial slope and medial/lateral ligament balance on knee flexion in total knee arthroplasty.

PURPOSE: The intra-operative femorotibial joint gap and ligament balance, the predictors affecting these gaps and their balances, as well as the postoperative knee flexion, were examined. These factors were assessed radiographically after a posterior cruciate-retaining total knee arthroplasty (TKA). The posterior condylar offset and posterior tibial slope have been reported as the most important intra-operative factors affecting cruciate-retaining-type TKAs. The joint gap and balance have not been investigated in assessments of the posterior condylar offset and the posterior tibial slope. METHODS: The femorotibial gap and medial/lateral ligament balance were measured with an offset-type tensor. The femorotibial gaps were measured at 0°, 45°, 90° and 135° of knee flexion, and various gap changes were calculated at 0°-90° and 0°-135°. Cruciate-retaining-type arthroplasties were performed in 98 knees with varus osteoarthritis. RESULTS: The 0°-90° femorotibial gap change was strongly affected by the posterior condylar offset value (postoperative posterior condylar offset subtracted by the preoperative posterior condylar offset). The 0°-135° femorotibial gap change was significantly correlated with the posterior tibial slope and the 135° medial/lateral ligament balance. The postoperative flexion angle was positively correlated with the preoperative flexion angle, γ angle and the posterior tibial slope. Multiple-regression analysis demonstrated that the preoperative flexion angle, γ angle, posterior tibial slope and 90° medial/lateral ligament balance were significant independent factors for the postoperative knee flexion angle. The flexion angle change (postoperative flexion angle subtracted by the preoperative flexion angle) was also strongly correlated with the preoperative flexion angle, posterior tibial slope and 90° medial/lateral ligament balance. CONCLUSION: The postoperative flexion angle is affected by multiple factors, especially in cruciate-retaining-type TKAs. However, it is important to pay attention not only to the posterior tibial slope, but also to the flexion medial/lateral ligament balance during surgery. A cruciate-retaining-type TKA has the potential to achieve both stability and a wide range of motion and to improve the patients' activities of daily living.

Theoretically optimum position of the prosthesis in total hip arthroplasty to fulfill the severe range of motion criteria due to neck impingement.

BACKGROUND: The purpose of this investigation is to determine the optimum position of the prosthesis in total hip arthroplasty for reducing neck impingement using a mathematical formula. METHODS: We calculated the cup inclination, cup anteversion, and stem antetorsion in cases with various sizes of femoral head (28, 32, 36, and 44 mm in diameter) to fulfill severe range of motion criteria: (1) flexion more than 120°, (2) extension more than 30°, (3) internal rotation at 90° flexion more than 60°, and (4) external rotation at neutral more than 40°. RESULTS: When the areas to fulfill the severe range of motion criteria were compared by femoral head diameter, the area for 28 mm was extremely small relative to those of 32, 36, and 44 mm. Theoretically, the optimum position of the prosthesis in total hip arthroplasty without neck impingement should be oriented at a cup inclination of 45° combined with the cup anteversion and stem antetorsion so that the sum of the cup anteversion plus 0.7 times the stem antetorsion equals 42° with a head diameter more than 32 mm. This study also recommends the optimum position of the prosthesis as 45° cup inclination, 25° cup anteversion, and 25° stem antetorsion when the surgeon can choose a freely adjustable modular stem system. However, this theory assumes that the pelvic inclination has no changes caused by aging and can be validated in the lying, sitting, and standing positions. CONCLUSIONS: The prosthesis in total hip arthroplasty without neck impingement should be oriented at a cup inclination of 45° combined with cup anteversion and stem antetorsion determined by the formula: cup anteversion + 0.7 × stem antetorsion = 42°. A range of acceptable positions would be more helpful and realistic to a surgeon trying to ensure adequate prosthesis positions.

Efficacy of bone marrow mononuclear cells to promote bone regeneration compared with isolated CD34+ cells from the same volume of aspirate.

Autologous bone marrow mononuclear cell (BMMNC) transplantation is currently an emerging clinical treatment in the orthopedic as well as cardiovascular fields. It is believed that the therapeutic effect of the BMMNCs is due to neovascularization enhanced by the CD34(+) cells contained therein, which include endothelial progenitor cells. However, isolation of the CD34(+) cell fraction for clinical application has many disadvantages such as cost and invasiveness related to cell mobilization with cytokine. To investigate whether a purification step is in fact necessary for bone regeneration, we separated BMMNCs, CD34(+), and CD34(-) cells from the same initial volume of rabbit bone marrow aspirates. We then transplanted them back into a femoral bone defect of the same rabbit together with atelocollagen gel and basic fibroblast growth factor (bFGF) and evaluated neovascularization and bone regeneration up to 8 weeks after transplantation. The greatest potential for neovascularization and bone regeneration medicated by cells from the same volume of bone marrow aspirate was found in the BMMNC group. Although purified CD34(+) cells might be an ideal cell source, BMMNCs could be a practical and feasible cell source for bone regeneration in present clinical settings with limited cost, availability of materials, and technical issues for transplantation.

Serum interleukin 8 levels correlate with synovial fluid levels in patients with aseptic loosening of hip prosthesis.

Levels of inflammatory cytokines (tumor necrosis factor alpha, interleukin [IL] 6, and IL-8) in serum from patients with osteolysis on radiographs after hip arthroplasty [osteolysis(+), n = 28], patients without osteolysis after hip arthroplasty [osteolysis(-), n = 24], and nonoperated healthy subjects [controls, n = 20] were determined. In addition, cytokine levels in synovial fluid from patients undergoing revision total hip arthroplasty (n = 14) for loosening were measured and compared with each other and with the area of osteolysis on radiographs. Serum IL-6 and IL-8 levels were significantly higher in the osteolysis(+) group than in the osteolysis(-) or the control groups. Furthermore, a significant correlation was found between the serum and synovial fluid IL-8 levels and between synovial fluid IL-8 levels and the area of osteolysis in patients undergoing revision total hip arthroplasty. Therefore, serum IL-8 levels could be a useful periprosthetic osteolysis marker.

Natural course of the minimally symptomatic nonoperated hip in patients with bilateral hip dysplasia treated with contralateral rotational acetabular osteotomy.

BACKGROUND: The purpose of this study was to investigate the natural course of the minimally symptomatic nonoperated hip in patients with pre-osteoarthritis or early osteoarthritis in bilaterally dysplastic hips. METHODS: The material consisted of 61 patients with bilaterally dysplastic hips who underwent rotational acetabular osteotomy in their symptomatic hip and nonoperative treatment in their asymptomatic or minimally symptomatic hip. The average follow-up was 10.1 years (range 7.0-15.6 years), and the average age at the time of surgery was 38.2 years (range 20-58 years). All patients were divided into two groups by joint congruity of the nonoperated hip at surgery with rotational acetabular osteotomy. RESULTS: On radiographic assessment, 1 of the 35 pre-osteoarthritis hips had developed early osteoarthritis, and 6 of the 26 early osteoarthritis hips had progressed to advanced osteoarthritis. The Kaplan-Meier survivorship analysis for the whole group of nonoperated hips, with radiographic progression of osteoarthritis as the endpoint, predicted a 10-year survival rate of 83.7% (95% confidence interval 70%-98%). Significant differences were observed in the radiographic stage (pre- and early osteoarthritis group, P=0.015) and joint congruity (good and fair group, P=0.005). CONCLUSIONS: If the contralateral nonoperated hip has good joint congruity, minimal symptoms, and no or little radiographic change in patients with pre- or early osteoarthritis and bilateral acetabular dysplasia, the probability of radiographic progression is low.

Bone remodeling of a femoral head after transtrochanteric rotational osteotomy for osteonecrosis associated with slipped capital femoral epiphysis: a case report.

A rare case of a 12-year-old boy on whom a joint-preserving operation for osteonecrosis after slipped capital femoral epiphysis (SCFE) was performed, is described. Firstly, in situ pinning was performed for acute-on-chronic SCFE. However, osteonecrosis and collapse of the femoral head occurred at 7 months after surgery. Secondly, transtrochanteric rotational osteotomy (TRO) was performed against progression of the collapse of the femoral head. Eight years of X-ray observation revealed bone remodeling at the osteonecrotic region. No documentation has been reported about the potential of bone remodeling of a femoral head with osteonecrosis after SCFE. This case indicates that a joint-preserving operation such as TRO is capable of promoting bone remodeling in such circumstances.

Neovascularization and bone regeneration by implantation of autologous bone marrow mononuclear cells.

We examined whether transplantation of autologous bone marrow mononuclear cells (BM-MNCs) can augment neovascularization and bone regeneration of bone marrow in femoral bone defects of rabbits. Gelatin microspheres containing basic fibroblast growth factor (bFGF) were prepared for the controlled release of bFGF. To evaluate the in vivo effect of implanted BM-MNCs, we created bone defects in the rabbit medial femoral condyle, and implanted into them 5 x 10(6) fluorescent-labeled autologous BM-MNCs together with gelatin microspheres containing 10 microg bFGF on an atelocollagen gel scaffold. The four experimental groups, which were Atelocollagen gel (Col), Col + 5 x 10(6) BM-MNCs, Col + 10 microg bFGF, and Col + 5 x 10(6) BM-MNCs + 10 microg bFGF, were implanted into the sites of the prepared defects using Atelocollagen gel as a scaffold. The autologous BM-MNCs expressed CD31, an endothelial lineage cell marker, and induced efficient neovascularization at the implanted site 2 weeks after implantation. Capillary density in Col + BM-MNCs + bFGF was significantly large compared with other groups. This combination also enhanced regeneration of the bone defect after 8 weeks to a significantly greater extent than either BM-MNCs or bFGF on their own. In summary, these findings demonstrate that a combination of BM-MNCs and bFGF gelatin hydrogel enhance the neovascularization and the osteoinductive ability, resulting in bone regeneration.

Progressive collapse of transposed necrotic area after transtrochanteric rotational osteotomy for osteonecrosis of the femoral head induces osteoarthritic change. Mid-term results of transtrochanteric rotational osteotomy for osteonecrosis of the femoral head.

INTRODUCTION: Osteonecrosis of the femoral head is usually progressive, and once collapse of the femoral head develops, joint destruction almost invariably follows. Therefore, for partial osteonecrosis of the femoral head, various types of osteotomies have been developed in an attempt to save the femoral head and maintain the natural function of the hip joint. MATERIALS AND METHODS: We reviewed 25 hips in 21 patients for a mean follow-up period of 6.4 years after Sugioka's transtrochanteric anterior rotational osteotomy for osteonecrosis of the femoral head. RESULTS: The clinical results were excellent or good in 20 hips (80%), and radiological success was observed in 15 hips (60%) with an absence of both collapse of the newly established weight-bearing area of the femoral head and narrowing of the joint space. Progressive collapse of the transposed necrotic area was noted in 10 hips (40%), and of these 10 hips, narrowing of the joint space was observed in 7 (70%) at follow-up. A significant correlation was demonstrated between progressive collapse of the transposed necrotic area and narrowing of the joint space. Growth of an osteophyte of the femoral head was observed postoperatively in 16 hips (64%), particularly at anterior and lateral sites of the femoral head. CONCLUSIONS: Though collapse of a new weight-bearing area can be prevented, progressive collapse of the transposed necrotic area induces anterior joint instability, giving rise to osteoarthritic change. It is therefore concluded that prevention of the collapse of the transposed necrotic area is important for satisfactory long-term results.

Bone remodeling after impacted cancellous allograft in revision hip arthroplasty based on (99m)Tc-MDP bone scintigraphy.

INTRODUCTION: Impacted cancellous allograft for the femur reported by Gie et al. (1993) has resulted in a good outcome. Revascularization of the graft was proven with plain radiographs or in some cases, biopsy and autopsy. We have attempted to document the change in appearance of impacted cancellous allograft in the femur over time on scintigraphic scans. MATERIALS AND METHODS: Bone scintigraphy was conducted following total hip arthroplasty of 20 hips without complication using impacted cancellous allograft. At 6 weeks, 1, 2 and 4 years postoperatively, uptake at 5 regions of interest around the femoral component sites was measured. RESULTS: At all 5 regions of interest, uptake was significantly decreased at 1 year postoperatively compared with that at 6 weeks postoperatively. At 2 and 4 years postoperatively, uptake was about 2-fold that of the normal femur in the greater trochanter, lesser trochanter, and stem tip and had decreased to almost the normal level at the lateral stem and medial stem. CONCLUSION: In revision hip arthroplasty using impacted cancellous allograft, remodeling of the grafted bone of the femur was still incomplete, particularly at the greater trochanter, lesser trochanter, and stem tip even after 4 years postoperatively. It is felt that further time is required for remodeling.

Bone-preserving prosthesis with a single axis for treating osteonecrosis of the femoral head: midterm results for the thrust plate hip prosthesis.

We studied 27 patients (31 joints) who underwent total hip arthroplasty (THA) using the thrust plate hip prosthesis (TPP) for osteonecrosis of the femoral head. The mean follow-up period was 56 months (range 38-72 months). Clinical evaluation by the Merle d'Aubigne and Postel system showed a significant improvement from a preoperative mean score of 8.1 to a final mean follow-up score of 16.6. Mechanical loosening developed about 1 year postoperatively in one joint with a bone defect. Grade 1 stress shielding was observed in four joints. Although indications for the TPP are restricted to certain cases, unlike the conventional intramedullary stem, much can be expected of TPP. It is an outstanding prosthesis for osteonecrosis of the femoral head of young patients in terms of bone preservation and physiological load transfer.

Second- and third-generation Omniflex modular femoral stem: results 3 to 8 years after surgery.

Primary cementless total hip arthroplasty (THA) using the Omniflex modular femoral stem was conducted on 73 hips in 70 patients. The arc deposition (AD)-type stem was used in 26 hips, and the hydroxyapatite (HA)-type stem was used in 47 hips. The mean follow-up period of patients in the AD group was 78 (range, 61-96) months and that of patients in the HA group was 52 (range, 36-61) months. Clinically, improvement in the Harris hip score occurred in all cases. Thigh pain was reported in 3 (11.5%) AD hips and in 1 (2.1%) HA hip. Radiologically, bone ingrowth fixation was seen in 88.5% of the AD group and in 97.9% of the HA group. No subtrochanteric stress shielding, stem migration of > 2 mm, or revision THA occurred. The second- and third- generation Omniflex stems are useful cementless devices resulting in favorable initial biologic fixation and little bone atrophy at mid-term follow-up.

Effects on articular cartilage of subchondral replacement with polymethylmethacrylate and calcium phosphate cement.

Bone defects were created in rabbit medial femoral condyle in a model where subchondral bone was completely removed or about 2 mm of subchondral bone was maintained. Groups without augmentation and augmented with autogenous bone, polymethylmethacrylate, or calcium phosphate cement were sacrificed at 3, 12, and 24 weeks for evaluation of articular cartilage and observation of bone formation. In the model in which subchondral bone was completely removed, collapse of the subchondral bone together with exfoliation and prolapse of cartilage developed early in all cases. In the model in which 2 mm of subchondral bone was maintained, degeneration of articular cartilage developed at 12 weeks in the group augmented with polymethylmethacrylate, showing a significant difference when compared to the contralateral untreated control group. The group augmented with calcium phosphate cement did not demonstrate any evident difference from the control group. Mechanical properties after subchondral replacement did not differ between the groups augmented with polymethylmethacrylate and calcium phosphate cement, although calcium phosphate cement was considered histologically superior. Calcium phosphate cement was a reliable subchondral replacement material when the bone defect is adjacent to the articular cartilage.